21001011221100 has 72 divisors (see below), whose sum is σ = 60864366931200. Its totient is φ = 5590920246080.

The previous prime is 21001011221093. The next prime is 21001011221123. The reversal of 21001011221100 is 112211010012.

It is a super-2 number, since 2×21001011221100² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 58253832 + ... + 58613231.

It is an arithmetic number, because the mean of its divisors is an integer number (845338429600).

Almost surely, 2^{21001011221100} is an apocalyptic number.

21001011221100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001011221100 is an abundant number, since it is smaller than the sum of its proper divisors (39863355710100).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21001011221100 is a wasteful number, since it uses less digits than its factorization.

21001011221100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116867679 (or 116867672 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21001011221100 its reverse (112211010012), we get a palindrome (21113222231112).

The spelling of 21001011221100 in words is "twenty-one trillion, one billion, eleven million, two hundred twenty-one thousand, one hundred".